SYSTEMATIC 103 



fine, crisp, retractively oblique radial threads which cross the spiral cords, rendering them minutely 

 gemmate. Whorls strongly convex, slightly flattened below the suture on the early whorls, but resolving 

 into a slight subsutural concavity over the last whorl. Suture impressed to adpressed. Spire equal to 

 height of aperture. Umbilicus wide, perspective outwardly, one-third major diameter of the base but 

 rapidly contracted within to one-ninth the diameter of the base. Aperture circular, discontinuous, outer 

 lip thin ; columellar lip slightly thickened and reflexed ; parietal wall with a very thin glaze that does not 

 obscure the sculpture. Colour pale pinkish buff, interior of the aperture faintly iridescent. Operculum 

 circular, thin, horny, yellowish brown, of about eight spirals. 

 Diameter 12-0 mm.; height 1175 mm. (holotype). 



Type locality. St. WS 766. Between Falkland Is. and Argentina, 45 13' S, 59 56' 30" W, 

 18 Oct. 1931, 545 m. 



St. WS 228. North-east of Falkland Is., 50 50' S, 56 58' W, 30 June 1928, 229-236 m. 



St. WS 237. North of Falkland Is., 46 00' S, 6o° 05' W, 7 July 1928, 150 m. 



St. WS 244. West of Falkland Is., 52 00' S, 62 40' W, 18 July 1928, 253 m.* 



St. WS 869. Between Falkland Is. and Patagonia, 52 15' 30" S, 64 13' 45" W, 31 Mar. 1932, 187-0 m. 



Dentition. Fig. G, 1 1 , p. 189. 10 + 5 + 1 + 5 + 10. The cusps on the first and second laterals are excep- 

 tionally long. Lateral number 3 has a very broad base and numbers 4 and 5 are large, long and hooked, 

 closely resembling in form the innermost enlarged marginals of the Calliostomids. In the figure only 

 the upper portions of numbers 4 and 5 are drawn, and they are shown in relation to the central and 

 laterals 1-3, but from the row immediately below. The two outer laterals are actually superimposed 

 upon numbers 2 and 3. The marginals are long, slender and curved. 



Animal. Head narrow behind but broad in front, with a deeply laciniated fringe overhanging the 

 small mouth. In front of the mouth there are folded laciniated lappets. Epipodial fringe with three 

 slender tentacles, anterior one long, others reducing in size towards the head (Fig. D, 3). 



Family LIOTIIDAE 



Genus Cirsonella Angas, 1877 



_, . , Type: Cirsonella australis Angas 



Cirsonella extrema 1 hiele J r 



Cirsonella extrema Thiele, 1912, p. 191, pi. n, fig. 23. 

 Type locality. Gauss Station, Davis Sea. 

 St. 1660. Ross Sea, 74 46-4' S, 178 23-4' E, 351 m. (one empty shell). 



Genus Brookula Iredale, 191 2 

 Type (o.d.) : Brookula stibarochila Iredale, Kermadec Islands 

 The following four species are certainly congeneric and conform with the superficial features of 

 Brookula. However, since the soft parts of these minute shells are unknown, the generic identity of 

 these antarctic and subantarctic species of the American Quadrant is provisional only. 



Brookula calypso (Melvill & Standen) 



Cyclostrema calypso Melvill & Standen, 1912, p. 345, pi. 1, fig. 3. 

 Type locality. Burdwood Bank, south of Falkland Is., 54 25' S, 57° 32' W, 56 fathoms. 

 St. 51. Off Eddystone Rock, east of Falkland Is., from 7 miles N 50 E to 76 miles N 63° E of Eddystone Rock, 

 4 May 1926, 115 m. 

 * The single half-grown example from St. WS 244 is more definitely shouldered, but is otherwise typical. 



